Automotive catalysts operate on the principle of heterogeneous catalysis, where the catalyst provides a surface for chemical reactions to occur between the exhaust gases. The catalytic converter typically contains a ceramic or metallic substrate coated with a combination of precious metals such as platinum (Pt), palladium (Pd), and rhodium (Rh). These metals serve as the active catalytic sites. The catalyst promotes the following key reactions:
Oxidation of CO to CO2: CO + O2 â CO2 Oxidation of HC to CO2 and H2O: CxHy + O2 â CO2 + H2O Reduction of NOx to N2: 2NOx â xO2 + N2
